Guta Percher/Ebony question

[Flatliner]

I recently made a bow for a fella who's dad has a dry country hardwood export business and as part payment for the bow he has given me a couple of Ute loads of assorted logs including Black Gidgee, False Sandal wood, Orange Box (which looks like some kind of very finely grained oak), real Sandal wood, something he calls Aust Ebony, (which is in fact the ebonized core of some tree he couldn't name and some Guta Percher which is a type of Asian rubber tree that was introduced in the fifties has gone a bit feral in northern Australia (beautiful timber).

I've googled Guta Percher and the Ebony but can't find anything on the mechanical properties of them.

So my question is has anyone used either of these timbers or know the mechanical properties?

Here's some photos.

From bottom to top in the first photo; Guta Percher, Sandalwood, Ebony, Guta Percher and the orange box.

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Guta Percher.

SDC12677.JPG (69.37 KiB) Viewed 2747 times

Ebony.

SDC12678.JPG (68.57 KiB) Viewed 2747 times

Cheers, Rob.

[Goatchaser]

I can't help, but fingers crossed that ebony is usable, would be great to see in a bow.

[bigbob]

Been doing a bit of searching myself Rob and the Gutta Percha tree is predominately used for its latex type sap which is used in orthodontic work [teeth]Its found in south east Asia and apparently in Northern Australia, but it gets hazy as it is compared to another species Excoeria parvifolia which has a toxic sap. It has been used in furniture and is also called Northern Birch. Can't find any reference to the properties of the timber though.

[Flatliner]

I can't help, but fingers crossed that ebony is usable, would be great to see in a bow.

Yeah that's what I'm hoping too Sean.

Sounds like you got much the same result as I did Bob.

Rob.

[Hamish]

Hi Rob, I've seen that site and have wondered about getting some stuff too, I think they had a min 500kg order.
I'd be surprised if most of that stuff wouldn't make sweet all wood bows, either self or laminated, backed with hickory or boo, providing it is straightgrained and free of defect.
I'd try backing some stuff with hickory, and seeing if the belly holds up in compression, then trying it as a self bow if successful. Definite good for risers of glass bows etc. If you want to send some stuff my way to try out, give me a pm, maybe we could come to an agreement?
I look forward to seeing your experiments.
Hamish.

[RobHunter]

Hey Rob

http://www.ttit.id.au/treepages/austebony.htm

Found this with a speies name

rgds

Another Rob

[bigbob]

That link is the same site I often go to Rob H , checking Aussie timbers. Quite useful, and diaspora is often called the Australian Ebony.Only the heartwood seems tp produce the ebony colour and is prone to checking. Rob N 's logs seem to show a bit of that.

[Flatliner]

Hey Rob

http://www.ttit.id.au/treepages/austebony.htm

Found this with a speies name

rgds

Another Rob

Thanks Rob, I have seen that site too, but no mechanical properties mentioned there either.

And yeah Bob it is checking quite badly, I've sealed the ends but isn't helping much.

Hey Hamish,
I won't be doing anything with it for perhaps a year, got to let it dry properly, hopefully there will be a little left without cracks in it. I'll let you know if I have any to spare.

Rob.

[Hamish]

Dense timbers can be hard to dry without checking. I usually seal the entire surface with a couple of coats of PVA glue, then leave them in a cool, dry spot, indoors. Even then you can still get checks.
Breaking them down into quarter logs really helps to relieve stress and stops the timber from tearing itself apart as it dries.

[Flatliner]

Hey Hamish,
thanks for the good advice but they were already checked when I got them. I sealed the ends which might help a bit and I just haven't had time to mill them up yet. I usually try to mill and stack green timbers to season as soon as I get them but you know what it's like,,,, When it rains it pours.

Cheers, Rob.